The way I see it, deer are the masters of their domain as we are of ours. They can tell the difference between another deer stepping on and breaking twigs and you breaking twigs. Although the sound might appear the same to us, it is a different tone or pitch that only "deer" ears can differentiate. In the same way, they know a human when they smell one.

I think it doesn't matter how well you prep yourself, there's no way to make yourself so scent free that deer can't smell you at all. I've seen posts where guys have said they've been detected when taking even the most extreme scent control measures. My take is that even if you were in full body scent lock suits, the deer could still pick up your scent just from you simply breathing.

I wish we had a few scientists on the board to shed some insight but what do you guys think? I believe that as long as you are playing the wind, you can be stinky as a gasoline/oil drenched mechanic and still pull it off. If the deer are upwind, they can't smell you period.